Pressure releasing device



Aug. 27, 1935. H. PITTLICK PRESSURE RELEASING DEVICE Filed July 7, 1932 [/7 Van for flflwrann FIZZ/[6% Patented Aug. 27, 1935 zsizsn PRESSURE RELEASING DEVICE Hermann Pittlick, llllerne-Sodingen, Germany; @lga Pittlick, ne Liebner, administratrix of said Hermann Pittlick, deceased, assignor to Hochdruck-Apparate-Bau G. m. b. H., Dortmund, Germany Application July 7, 1932, Serial No. 621,320 In Germany July 11, 1931 -8 Claims.

My invention relates to a pressure releasing device serving for discharging erosive fluid suspensions and the like from reaction vessels in which they are stored. under pressure.

" .-,The discharging of solids, liquids, gases or mixtures thereof from a chamber, for instance from a reaction chamber, in which they are stored under high pressure, against a much "lower, for instance, atmospheric pressure, involves considerable difficulties on account of the high pressure gradient and high flow velocity of the substances. The substances or mixtures often possesserosive,

abrasiveand corrosive properties which are detrimental to the pipe lines, valves, etc., through which the flowing substances are discharged.

It is an object of my invention to eliminate these difficulties. To this end I provide means whereby the pressure gradient between the substanceto be discharged and the medium into which it is discharged, is reduced to a limit within which objectionably high velocities are not attained. F

For instance, if it is desired to discharge an erosive fluid suspension which may be asolid or a liquid suspended in a gas or liquid, into the ambient air, I may proceed as follows: I employ an expansion chamber which in effect is a pressurereleasing pump or a pressure lock and in which at the beginning of a cycle, the residual mixture from a previous cycle is compressed to a pressure which may be equal to the pressure in the pressure vessel or reaction chamber and at any rate is so determined that the gradient between the pressure in the chamber and the initial compression 5 pressure will not bring about an unduly high flow velocity. Obviously the pressure gradient and the resulting velocity of flow must be determined in conformity with the erosive or other detrimental properties of the media to-be discharged. When the desired initial compression pressure has been attained, fresh mixture from the chamber is admitt'ed to the mixture which has already been compressed, and the whole is expanded down to a certain pressure which may be equal to the pressure of the ambient air. At this pressure part of the mixture is discharged the discharge being cut off before all of the mixture has been completely discharged. The residual mixture is then compressed again up to the initial compression pressure, and a fresh cycle is started.

In the manner described, the liquid or mixture is discharged from the reaction chamber against a pressure which may be equal to its own pressure and under all conditions must be so related to its own pressure that undesirably high flow velocity will not occur. After the pressure on the liquid gas or mixture has been released, it is finally discharged at a pressure which may be equal to the pressure against which it is discharged, for instance, the pressure of the ambient air, and must be so determined that high pressure gradients at the initial and at the final stages of the discharging operation are avoided, and the discharge occurs at a flow velocity which will not bring about detrimental erosive or other actions.

In the drawing afiixed to this specification and forming part thereof a pressure diagram and a pressure releasing device embodying my invention, are illustrated diagrammatically by way of example. s

In the drawing:- J Fig. 1 is the pressure diagram, and Figs. 2 to 5 are axial sections of the releasing device, showing the several stages of the discharging operation. Referring now to the drawing, and first to Fig. 1, pressures are plotted against piston strokes in the usual manner. At a, a residual amount of fluid suspension which is still present after the completion of a cycle, has been compressed to the initial pressure of the next cycle, which in the present instance is assumed to be equal to the pressure in the reservoir or reaction chamber. From a to b the inlet of the cylinder is held open and the suspension flows in at a substantially uniform pressure. At 21, the admission of fresh suspension from the reservoir is cut off and the suspension initially present plus the fresh suspension is expanded. The outlet is opened at 0 when a predetermined pressure has been attained which in the present instance is assumed to be substantially equal to the pressure ofv the ambient air. The suspension is now discharged under this uniform pressure from c to d. At d,-the outlet is cut oif and the residuum which is still present, is compressed to the initial pressure for the next cycle. The cut-off at dmust be so timed that the amount still present is sufficient to make up the initial pressure for the next cycle. The operation a to b to 0 represents the expansion stroke and c to d to a the compression stroke of the piston. 1

Referring now to Figs. 2 to ,5, i is a cylinder, with a piston 2, a piston rod 21, a connecting rod a crank 5 and a crank shaft 5. l is the inlet, and 8 is the outlet valve. 9 is a reservoir, for instance, a reaction chamber, which contains the fluid suspension to be discharged.

[0 is a pipe the expansion stroke.

been opened by its cam it at or near the outer 'fresh cycle begins. Y

extending from the reservoir 9 to the casing H of the inlet valve 1 which is here shown as a ball valve on a seat l2, with a pusher i3 and a cam M on a cam shaft l5. The outlet valve 8 is arrangedin a casing E6 on a seat ll, 58 is a dischargepipe connecting the casing to the atmosphere, i9 is a push rod, 26 is a cam and 26 is a cam shaft for operating the outlet valve. The casings ii and I6 are connected to the outer end of the cylinder i.

Any suitable mechanism may be provided for operating the cams i i and 20. .By way of ex-. ample in Fig. 2 I have .shown a conventional mechanism which includes bevel gearing 22, 23 and a shaft 24 for rotating the shaft E5 of cam i4, and bevel gearing 25, 26 and a shaft 2i for rotating the shaft 2i of cam 28. The shafts 2t;

and 2'! are rotated from a shaft 23 through a Worm 29 and a worm wheel 36, and a worm 3! and aworm wheel 32, respectively. Rotation is imparted to the shaft 28 through bevel gearing 33, 3 an intermediate shaft 35, a bevel pinion 35 at the upper end of the intermediate shaft 'mixture from the chamber, the discharge of the mixture from the cylinder] after it has expanded therein, and the re-compression of the mixture which is left in the cylinder after the outlet valve 8 has closed at d, Fig. 1. A certain amount of energy is transmitted to the piston 2 'of the'compre'ssor'during the expansion stroke a'-bc; but this is a secondary consideration.

Fig. 2 shows the position of the parts during The inlet valve 7 has dead centre position of the piston and held open until the end of the admission period. The outlet valve 8 is closed. At the closing of the inlet valve 1 the expansion begins? Fig. 3 shows the piston 2 near the end of the expansion stroke. The outlet valve'8 is still closed but is opened at or near the inner dead centre position of the piston 2, Fig. l, whereupon the discharge of the mixture through pipe l3 begins at the start'of 'until the beginning of the compression stroke while the inlet valve 7 remains closed. Near the completion of the compression stroke outlet valve ers l3 and i9, under the control of their cams, follow the automatically opened valves and hold them open for the required periods.

Obviously it is necessary that the-properties of the material to be. discharged from .the reservoir or. reaction chamber 9 should be considered in performing the operation of the pump.

. As mentioned, the object of my invention is also attained if the substance is not quite under "the reservoir p'ressurt at point a, Fig. 1, and is 3 is closed in order to entrap in the cylinder the residual amount of suspension which is required for building up the initial pressure at a, Fig. 1.

The inlet valve i remains closed and the contents opens at 'or near the outer dead centre and a The energy which'is liberated during the cycle may be utilized in any suitable manner.

' It is not necessary thatthe inlet valve '5 and the' outlet valve 8, or one of them should be positively'controlled by'their respective pushers l3 and i9 throughout, but they may be partly automatic, the inlet valve l opening automatically as soon as the compression pressure at a, Fig. 1, begins to overstep the reservoir pressure,

and the outlet valve 8 opening automatically as soon as the expansion pressure begins to understep the pressure of theambient air. The pushnot quite under the pressure of theambient air I at point 0 but whenever the respective pressures are so selected that velocities at which detrimental action on the valves etc., may occur, are avoided.

Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the advantages thereof.

action chamber to a point of materially reduced pressure, which comprises exhausting the mixture from the high pressure chamber into an expansion zone containing acompressed fluid material at a predetermined pressure such that the velocity of flow of the mixture into the expansion zone is of a non-erosive order, expanding the mixture in the expansion zone to a pressure approaching said materially reduced pressure, then discharging a portion of the expanded mixture from theexpansion zone to said point of reduced pressure While retaining another portion thereof in the expansion zone, compressing the retained portion of the mixture in the expansion zone to said predetermined pressure for use as said compressed fluid material in the next cycle of operation, and repeating the operating cycle as aforesaid.

2. The process of claim 1 wherein the mixture is expanded in said expansion zone to a pressure below that 'of the said materially reduced pressure and is compressed in said zone to a pressure above that of said high pressure zone.

3. A method for discharging compressible and erosive fluid suspensions from high pressure reaction chambers to a point of relatively low pressure, which comprises exhausting such' a suspension from a high pressure chamber into an expansion zone containing a compressed fluid material at substantially the pressure of the high pressure chamber, expanding'the resulting mixture in the expansion zone to substantially said relatively. low pressure, then discharging a portion of the expanded mixture from the expansion zone to said point of low pressure while retaining another portion thereof in the expansion zone, compressing the retained portion of the mixture in the expansion zone to substantially the pressure of the high pressurechamber to constitute said compressed fluid material for the next cycle of operation, and repeating the operating cycle as aforesaid.

4. In the discharge of compressible and erosive such a suspension from the high pressure chamber into an expansion'zone containing fluid material compressed to a pressure approaching that of the high pressure chamber, expanding the resulting mixture in the expansion zone to substantially atmospheric pressure, then discharging H a portion of the expanded mixture from the expansion zone, compressing the retained portion of the mixture in the expansion zone to a pressure approaching that of the high pressure chamher, and utilizing such compressed and retained portion of the mixture as said fluid material in another cycle of operation as aforesaid.

5. A device for releasing normally erosive fluid suspensions and the like under high pressures from reaction vessels Without the production of erosion, which comprises a cylinder, a piston, means for reciprocating saidpiston in said cylinder, thereby producing an expansion stroke and a compression stroke, means including a valve for introducing a fluid suspension under high pressure into said cylinder from said reaction vessel prior to the completion of said expansion stroke, means including a second valve for discharging the bulk of said fluid suspension from said cylinder prior to the completion of said compression stroke and under substantially atmospheric pressure, and operating means for opening and closing said valves cooperating with said reciprocating means to close said second valve prior tothe completion of said compression stroke thereby retaining in said cylinder suflicient fluid suspension to produce therein substantially the pressure of said reaction vessel upon completion of said compression stroke and at the point of opening of said first mentioned valve.

6. The device of claim 5 wherein said first valve is a check valve.

7. The device of claim 5 wherein both said first valve and said second valve are check valves.

8. The device of claim 5 wherein said operating means is adjusted to close said first valve prior to the completion of said expansion stroke.

' HERMANN PITTLICK. 

